AM2434: AM2434

Hi Kishor,

KISHOR KUMAR said:

I am using the adc_singleshot.c sample code. What changes need to be done to capture whole sine wave pulse in continuous mode instead of existing singleshot mode? 

Let me check what changes can be done in the existing code to change ADC mode to continuous, I will try to test something at my end and let you know.

KISHOR KUMAR said:

MAXADCSAMPLELOGSIZE is changed to 100, the code gets stuck in infinite loop. How to resolve this issue also?

Could you elaborate more on this MAXADCSAMPLELOGSIZE, have you made any changes in the existing singleshot ADC code and observing this issue? If so, let me know the changes, it would be helpful to debug the issue.

Best Regards,

Meet.

Hi Kishor,

It seems you only need to change the following setting to make it continuous:

adcConfig.mode             = ADC_OPERATION_MODE_SINGLE_SHOT; --> ADC_OPERATION_MODE_CONTINUOUS

Please refer to this thread, there are some additional recommendations: (+) LP-AM243: ADC Continuous Conversion Buffering? - Arm-based microcontrollers forum - Arm-based microcontrollers - TI E2E support forums

Best Regards,

Meet.

Changing this has no effect on the ADC sampled data, The sample data is same as the image provided earlier. How to sample the negative samples through the ADC. As currently, I am only able to get positive samples but those also not of proper waveform .  

Hi Kishor,

KISHOR KUMAR said:

those also not of proper waveform .  

This seems to be the limitation cause by the UART transmission. You mentioned you transfer the ADC result using UART, could you let me know the baudrate settings for the UART. Based on the baudrate, how many samples are transmitted will be affected leading to a distorted waveform as it doesn't have enough sample points.

KISHOR KUMAR said:

How to sample the negative samples through the ADC.

Could you let me know what is the peak-to-peak voltage of the sine waveform you are trying to sample using ADC?  Please note that in the single-ended mode ADC results positive binary weighted data ranging from 0 to (2¹² - 1) and the range of the input voltage is from REFN to REFP, that's why you are only observing the positive samples, you might have to use differential mode for this:

Another thing you can try is to give your signal a DC offset, so that the entire signal comes in the positive voltage range of REFN to REFP, while plotting the graph you can subtract the same offset from the ADC sample values.

Best Regards,

Meet.

Baud Rate is 9600.

This seems to be the limitation cause by the UART transmission. You mentioned you transfer the ADC result using UART, could you let me know the baudrate settings for the UART. Based on the baudrate, how many samples are transmitted will be affected leading to a distorted waveform as it doesn't have enough sample points.

Currently i am using Keysight Signal generator with amplitude of 1dBm and frequency of 10kHz. How to configure the differential mode and generally differential needs signal on two pins. How to configure for the same .

Could you let me know what is the peak-to-peak voltage of the sine waveform you are trying to sample using ADC?  Please note that in the single-ended mode ADC results positive binary weighted data ranging from 0 to (2¹² - 1) and the range of the input voltage is from REFN to REFP, that's why you are only observing the positive samples, you might have to use differential mode for this:

How to configure for the DC offset ?

Another thing you can try is to give your signal a DC offset, so that the entire signal comes in the positive voltage range of REFN to REFP, while plotting the graph you can subtract the same offset from the ADC sample values.

Thanks 

Kishor Kumar